Preface |
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vii | |
1 Galois theory of fields |
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1 | |
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1.1 Algebraic field extensions |
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1 | |
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4 | |
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1.3 Infinite Galois extensions |
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9 | |
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1.4 Interlude on category theory |
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15 | |
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1.5 Finite etale algebras |
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20 | |
2 Fundamental groups in topology |
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27 | |
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27 | |
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30 | |
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34 | |
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39 | |
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2.5 Locally constant sheaves and their classification |
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45 | |
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51 | |
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2.7 The RiemannHilbert correspondence |
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54 | |
3 Riemann surfaces |
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65 | |
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65 | |
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3.2 Local structure of holomorphic maps |
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67 | |
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3.3 Relation with field theory |
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72 | |
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3.4 The absolute Galois group of C(t) |
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78 | |
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3.5 An alternate approach: patching Galois covers |
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83 | |
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3.6 Topology of Riemann surfaces |
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86 | |
4 Fundamental groups of algebraic curves |
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93 | |
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4.1 Background in commutative algebra |
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93 | |
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4.2 Curves over an algebraically closed field |
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99 | |
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4.3 Affine curves over a general base field |
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105 | |
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110 | |
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4.5 Finite branched covers of normal curves |
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114 | |
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4.6 The algebraic fundamental group |
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119 | |
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4.7 The outer Galois action |
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123 | |
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4.8 Application to the inverse Galois problem |
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129 | |
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4.9 A survey of advanced results |
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134 | |
5 Fundamental groups of schemes |
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142 | |
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5.1 The vocabulary of schemes |
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142 | |
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5.2 Finite etale covers of schemes |
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152 | |
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5.3 Galois theory for finite etale covers |
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159 | |
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5.4 The algebraic fundamental group in the general case |
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166 | |
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5.5 First properties of the fundamental group |
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170 | |
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5.6 The homotopy exact sequence and applications |
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175 | |
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5.7 Structure theorems for the fundamental group |
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182 | |
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5.8 The abelianized fundamental group |
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193 | |
6 Tannakian fundamental groups |
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206 | |
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6.1 Affine group schemes and Hopf algebras |
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206 | |
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6.2 Categories of comodules |
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214 | |
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6.3 Tensor categories and the TannakaKrein theorem |
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222 | |
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6.4 Second interlude on category theory |
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228 | |
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6.5 Neutral Tannakian categories |
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232 | |
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6.6 Differential Galois groups |
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242 | |
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6.7 Nori's fundamental group scheme |
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248 | |
Bibliography |
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261 | |
Index |
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268 | |